[llvm] [X86] Narrow vXi32/vXi64 usubsat to vpsubusb/vpsubusw when LHS is known to fit in fewer bits (PR #206592)

[via llvm-commits]

sipher-01 wrote:

Hi @RKSimon,

 I’ve addressed the test failures, and the PR now passes ninja check-llvm-codegen-x86.

If there are any further changes needed, please let me know at your convenience. I understand you are busy, so if you need more time to review, I am happy to leave the PR as-is while I move on to work on other issues. Just let me know whenever you have a chance to take another look.

 Thank you for your time!

https://github.com/llvm/llvm-project/pull/206592